The invention pertains to a cylindrical grinding process performed on a pre-ground part, as well as the as-ground part resulting from the cylindrical grinding process performed on the pre-ground part. More specifically, the invention pertains to a cylindrical grinding process performed on a pre-ground part, as well as the as-ground part resulting from the cylindrical grinding process performed on the pre-ground part wherein the process removes material from the part so as to result in the as-ground part exhibiting a dimensional condition so that the as-ground part does not unacceptably deform under loading when in use.
During a metal cutting operation, any vibration between the cutting tool and the workpiece may result in undesirable cutting performance. For example, such vibration can result in a poor surface finish on the workpiece or an out-of-tolerance finished workpiece. In addition, any such vibration can cause the cutting tool, as well as the associated machine tool, to suffer premature damage. Still another problem associated with vibration between the cutting tool and the workpiece, especially in drilling operations, is high frequency noise. Such noise can render the work place environment less desirable. While the operator can reduce the cutting speed to achieve a reduction in the vibration between the cutting tool and the workpiece, such an action is not desirable because the material removal rate is decreased thereby leading to a decrease in the productivity of the material removal operation. Therefore, it would be highly desirable to provide a feature in a machine tool system that achieves vibration dampening so as to maintain a higher cutting speed. Further, it would be highly desirable to provide a feature in a machine tool system that achieves vibration dampening so as to reduce the generation of high frequency noise.
In one structure, a tool holder contains a bore that receives a sleeve, which in turn receives a tool, wherein the sleeve is under load through the forces necessary to retain the tool within the sleeve. Loading the sleeve can result in a deformation of the sleeve so that tolerances of the sleeve in certain locations (or regions) relative to the tool holder must be such so that these locations of the sleeve do not contact the corresponding surface of the bore. Heretofore, one way to reduce the instances of contacts between certain regions of the sleeve and the corresponding surfaces of the bore is to utilize larger tolerances. Yet, larger tolerances in this kind of system can result in adverse consequences.
For example, larger tolerances will result in greater amounts of accuracy run-out issues, wherein the cutting tool at the cutting tip will be out of alignment in relation to the centerline of the tool holder that contains the sleeve. This type of system inherently has run-out issues due to the locking screws pushing on the tool shank. Increasing the tolerance between sleeve and tool shank allows for the sleeve to be pushed further from the centerline.
In addition reduced accuracy produces poor machining quality. For instance the more run-out that a system has the more deviation there will be in the size and shape of a hole. Furthermore, the surface finish will also be affected and become less desirable. Other consequences of an increased tolerance can include reduced tool-life that is the result of too much movement of the tool shank and sleeve which may cause excess wear or chipping on the cutting surfaces.
Therefore, it becomes apparent that it would be highly desirable to provide a cylindrical grinding process which results in an as-ground part that performs in an acceptable fashion when the as-ground part is under load. In the case of a tool holder-sleeve assembly wherein the tool holder receives the sleeve, it would be highly desirable to provide such an assembly in which selected regions of the sleeve does not contact selected regions of the tool holder when the sleeve is under load. In the case of a tool holder-sleeve assembly wherein the tool holder has a bore that receives the sleeve, it would be highly desirable to provide such an assembly that does not necessitate larger tolerances to reduce the instances of contacts between the sleeve and the corresponding surfaces of the bore.